That smooth SpaceX launch? Turns out one of the engines came apart

Those of us who watched the live feed of last night's Falcon 9 launch could be forgiven for assuming that everything went according to plan. All the reports that came through over the audio were heavy on the word "nominal," and the craft successfully entered an orbit that has it on schedule to dock with the International Space Station on Wednesday. But over night, SpaceX released a slow-motion video of what they're calling an "anomaly."

Watch the video embedded below (starting at about the 27-second mark), though, and the term anomaly will look like a serious understatement. The video clearly shows a larger burst of flame within the normal plume of rocket exhaust, followed shortly by debris falling from the rocket.

The Falcon 9, as its name implies, has nine engines, and is designed to go to orbit if one of them fails. On-board computers will detect engine failure, cut the fuel supply, and then distribute the unused propellant to the remaining engines, allowing them to burn longer. This seems to be the case where that was required, and the computers came through. The engines are also built with protection to limit the damage in cases where a neighboring engine explodes, which appears to be the case here.

SpaceX has indicated that it will provide a more detailed report on the event later today. We'll update the story when that becomes available.

The remaining engines shrug off the apparent explosion of their neighbor.

Update:

SpaceX has released the following statement:

Approximately one minute and 19 seconds into last night’s launch, the Falcon 9 rocket detected an anomaly on one first stage engine. Initial data suggests that one of the rocket’s nine Merlin engines, Engine 1, lost pressure suddenly and an engine shutdown command was issued immediately. We know the engine did not explode, because we continued to receive data from it. Our review indicates that the fairing that protects the engine from aerodynamic loads ruptured due to the engine pressure release, and that none of Falcon 9’s other eight engines were impacted by this event.

As designed, the flight computer then recomputed a new ascent profile in real time to ensure Dragon’s entry into orbit for subsequent rendezvous and berthing with the ISS. This was achieved, and there was no effect on Dragon or the cargo resupply mission.

Falcon 9 did exactly what it was designed to do. Like the Saturn V, which experienced engine loss on two flights, Falcon 9 is designed to handle an engine out situation and still complete its mission.

This seems like a huge win for the SpaceX program - I can't say that I've ever seen a 'successful' launch where there was a catastrophic engine failure - the redundancy built into this thing has effectively saved the mission and millions of dollars.

I'm sure they will be trying to identify the cause of the failure and correct it for future missions, but the mere fact that it looks like this thing is going to make its scheduled rendezvous is huge.

The backup systems worked and the mission was accomplished despite an engine failure. Certainly they should work on making the engines more reliable, but the fact that the failure was correctly handled increases my confidence that they know what they are doing.

I'm really curious as to why nothing was said during the launch. An engine which undergoes rapid unplanned disassembly isn't likely to be missed in the telemetry feed. You didn't even hear someone in the announcer's background saying, "Holy shit, we lost number 4!"

Yeah, good for them for being able to handle an engine-out scenario, just like Saturn V was able to do 40+ years ago, but I have a feeling things wouldn't have ended so well if it had been an engine in the center of the cluster that had exploded, or if the one that did explode popped the other way. This is why I'm not terribly keen on the idea of Falcon Heavy sporting 27(!) engines. I'm pulling for SpaceX, but IMO the clustered engine approach is a liability and the sooner they can get the Merlin 2 engine in production, the better (not the least because it would enable the BFR that Elon wants to build so he can walk on Mars).

Yeah- it just seems like they recognized that planning for potential failures was a better option than putting all the eggs into one (or three) baskets. Seems like an eminently common sense plan (and for all I know it may be typical of modern rocket design), but then again sometimes it's things like this that show the genius. And yeah-not having to come back and tell NASA "Doh, guess we shoulda tested a few more times" is pretty great. So much money and engineering saved by the mission being successful despite a complete engine failure with explosion (!). Hell, I might be MORE likely to look at them knowing they are engineering this thing to get that payload delivered. Pretty cool stuff.

I'm really curious as to why nothing was said during the launch. An engine which undergoes rapid unplanned disassembly isn't likely to be missed in the telemetry feed. You didn't even hear someone in the announcer's background saying, "Holy shit, we lost number 4!"

Doesn't mean no one said it though, I wouldn't be surprised if that wasn't actually the exact words used.

Yeah, good for them for being able to handle an engine-out scenario, just like Saturn V was able to do 40+ years ago, but I have a feeling things wouldn't have ended so well if it had been an engine in the center of the cluster that had exploded, or if the one that did explode popped the other way. This is why I'm not terribly keen on the idea of Falcon Heavy sporting 27(!) engines. I'm pulling for SpaceX, but IMO the clustered engine approach is a liability and the sooner they can get the Merlin 2 engine in production, the better (not the least because it would enable the BFR that Elon wants to build so he can walk on Mars).

They designed for the possibility of an engine explosion (each engine separate and shielded), and the contingencies worked as planned. If they hadn't designed for it, there's no way it wouldn't have been catastrophic. Obviously, a launch where no engines explode is better than one where they do, but it's not exactly a rare occurrence with rockets, and they have just proven that their multi-engine design works. If a single or double engine rocket had a failure like that, it would have been game over.

I can't say that I've ever seen a 'successful' launch where there was a catastrophic engine failure

Apollo 13 launch comes pretty close. Alledgedly, center engine of first stage pogo'd around a meter vertically at a rate of 10Hz, which led to it nearly ripping free of its mountings and plowing into the underside of the rocket - which would have destroyed the vehicle for sure, as anyone might well understand. So the control system shut down that engine before anything truly bad happened.

Not catastrophic failure perhaps, but a close call nevertheless. And Murphy more than compensated later on in the Apollo 13 flight with that oxygen tank blowing up and all the assorted stuff that happened. Thankfully everybody involved in that mess were unharmed.

I'm going to go ahead and let them to iron all the bugs out before I start planning my space-vacation.

I guess then you must not drive, take trains or plane trips since you must be waiting for the bugs to be worked out of those transportation methods to make them 100% safe.

Come on, that's hardly fair. While 100% safe might not be a reasonable goal, you can hardly claim that (as of right now) rocket launches are equivalent to airplanes, or even cars, in safety.

I admit this has me morbidly curious about the percentage of fatalities in rockets and shuttles vs planes, trains, and automobiles.

It's an interesting question, although it might be, in fact, safer due to such high cost of mission failure so I'd guess they put a lot more money on a per-vehicle basis for safety/checks/reliability. Not sure, random guess, I haven't run the numbers so take it with a huge grain of proverbial salt.

Good planning turned a potential calamity into a minor footnote. Good work engineers at SpaceX. Everyone of these launches is going to be a learning experience. Hopefully they can get all the kinks out before they start ferrying people to the space station. 11 more flights to go.

This proves something that the Russians have known for decades. Rockets made with lots of smaller engines are far safer than those made with a few large engines.

Not really. The Soviet N1 rocket failed precisely because it used clusters of many engines instead of a few large engines, like the Saturn V. Many small engines are more likely to have a failure than a few large ones; this is well known and pretty obvious. The goal, of course, is to design the system so that it can tolerate engine failures, knowing that they're more likely to occur. N1 was also designed to tolerate individual engine failures, but the way these failures affected the entire rocket system was not adequately foreseen and the engine control systems were unable to properly assess the very complex situation and compensate in survivable manner . All four test launches failed on the first stage, primarily due to single engine failures in a complex system of 30 smaller modules. Interestingly enough, individually the engines used by the N1 were considered some of the most reliable engines available--in fact the Orbital Sciences Antares will use a descendant of them. But when you have so many of them, the likelihood of a single failure occurring is very high, and it's extremely difficult to ascertain how the failure of one engine, which can manifest in any number of hard to predict ways, will affect the operation of the rest of the system. This is part of the reason that you don't see so many 3+ engine airliners anymore--statistical analysis of engine failures convinced the regulatory agencies that having more than two engines wasn't really doing anything to improve system-wide redundancy, because while the odds of all of your engines shutting down were reduced, the odds of any engine failing catastrophically were increased.

That all said, the clustered design is cheaper to operate and SpaceX has done a very good job building in redundancy and anticipating failure modes. However, this failure is still a problem for them because there really is no way to predict every possible consequence of an exploding engine. The system survived this time, but might not next time. NASA will almost certainly require SpaceX to positively identify the cause of the failure and redesign before they go any further, pushing back the first manned Dragon flight.